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Abstract:

Discussed is a semiconductor LED package. The semiconductor LED package
includes a packet body having a cavity, a semiconductor light emitting
device in the cavity of the package body; and a plurality of reflective
frames, each of the reflective frames having a bottom frame in the cavity
of the package body, and at least two sidewall frames extending from the
bottom frame and inclined with respect to the bottom frame, wherein the
plurality of reflective frames are electrically separated from each
other.

Claims:

1. A semiconductor light emitting diode package comprising: a package
body having a cavity; a semiconductor light emitting device in the cavity
of the package body; and a plurality of reflective frames, each of the
reflective frames comprising: a bottom frame in the cavity of the package
body, and at least two side wall frames extending from the bottom frame
and inclined with respect to the bottom frame, wherein the plurality of
reflective frames are electrically separated from each other.

2. The semiconductor light emitting diode package according to claim 1,
wherein the plurality of reflective frames are extended to an outer
surface of the package body to function as electrodes.

3. The semiconductor light emitting diode package according to claim 1,
wherein the plurality of reflective frames are electrically connected to
the semiconductor light emitting device.

4. The semiconductor light emitting diode package according to claim 1,
wherein the semiconductor light emitting device is mounted on at least
one of the reflective frames.

5. The semiconductor light emitting diode package according to claim 1,
wherein the package body comprises a reflective frame partition that
separates the plurality of reflective frames from each other in the
cavity.

6. The semiconductor light emitting diode package according to claim 1,
wherein each of the plurality of reflective frames comprises a U-shaped
metal plate.

7. The semiconductor light emitting diode package according to claim 6,
wherein a reflective material is plated on surfaces of the metal plates.

8. The semiconductor light emitting diode package according to claim 1,
wherein at least one of the side wall frames is inclined with respect to
an axis perpendicular to the bottom frame.

9. The semiconductor light emitting diode package according to claim 8,
wherein the at least one of the side wall frames is inclined at an angle
of 15.degree. to 30.degree. with respect to the axis perpendicular to the
bottom frame.

11. The semiconductor light emitting diode package according to claim 1,
wherein an interval between the at least two side wall frames of each of
the reflective frames is 600 μm to 850 μm.

12. The semiconductor light emitting diode package according to claim 1,
wherein the cavity comprises a depth of 250 μm to 700 μm.

Description:

TECHNICAL FIELD

[0001] The embodiment relates to an LED (light emitting device) package
and a light unit having the same.

BACKGROUND ART

[0002] An LED constitutes a light emission source by using GaAs, AlGaAs,
GaN, in GaN and InGaAlP-based compound semiconductor materials, thereby
producing various color.

[0003] Such characteristics of the LED can be determined by materials,
colors, brightness and a brightness range of a compound semiconductor.
Further, the LED is provided as a package and is applied to various
fields comprising lighting indicators for displaying colors, character
indicators, image indicators and the like.

DISCLOSURE OF INVENTION

Technical Problem

[0004] The embodiment provides an LED package, in which a lead frame bent
in a multi-step is disposed at a bottom surface and at least one sidewall
defining a cavity, and a light unit having the same.

[0005] The embodiment provides an LED package, in which at least one of
plural lead frames is formed at a bottom surface and both sidewalls
defining a cavity, and a light unit having the same.

[0006] The embodiment provides an LED package comprising a lead frame,
which has sidewalls inclined at a predetermined angle or bent with a
predetermined curvature, and a light unit having the same.

Technical Solution

[0007] An embodiment provides an LED package comprising; a body comprising
a cavity at one side thereof; at least one of lead frames comprising a
bottom frame and a sidewall frame in the cavity; and a light emitting
device electrically connected with the lead frames.

[0008] An embodiment provides an LED package comprising; a body comprising
a cavity; a first lead frame comprising a bottom frame and at least one
sidewall frame at a first side of the cavity; a second lead frame
comprising a bottom frame at a second side of the cavity; and a light
emitting device electrically connected with the first and second lead
frames.

[0009] An embodiment provides a light unit comprising; a light emitting
apparatus comprising a plurality of LED packages; an optical guide plate
disposed at one side of the light emitting device; and an optical member
disposed above and/or below the optical guide plate, wherein the LED
package comprises a body comprising a cavity; at least one of lead frames
comprising bottom frame and a sidewall frame in the cavity; and a light
emitting device electrically connected with the lead frames.

Advantageous Effects

[0010] The embodiment can reduce optical loss in a cavity of an LED
package.

[0011] The embodiment can improve the light intensity at a center area in
a cavity of an LED package.

[0012] The embodiment can increase the amount of reflected light in a
cavity of an LED package by using a lead frame plated with reflective
metal or reflective material.

[0013] The embodiment can improve thermal resistance and thermal
characteristics of a lead frame of an LED package.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a front view showing an LED package according to an
embodiment;

[0015] FIG. 2 is a sectional view taken along an X axis of an LED package
shown in FIG. 1;

[0016] FIG. 3 is a perspective view showing the lead frame of FIG. 1

[0017] FIG. 4 is a sectional view taken along a Y axis of the LED package
shown in FIG. 1;

[0018] FIG. 5 is a sectional view showing an LED package having a lead
frame modified according to a first example embodiment;

[0019] FIG. 6 is a sectional view showing an LED package having a lead
frame modified according to a second example embodiment;

[0020] FIGS. 7 to 10 are views showing lead frames modified according to
third to sixth example embodiments;

[0021] FIG. 11 is a graph showing an angle of a lead frame as a function
of light intensity before and after the plating in the LED package of
FIG. 4;

[0022] FIG. 12 is a graph showing an angle of a lead frame as a function
of light velocity (or light amount) before and after the plating in the
LED package of FIG. 4; and

[0023] FIG. 13 is a perspective view showing a display device using the
LED package of FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] Hereinafter, an LED package according to an embodiment will be
described with reference to the accompanying drawing.

[0025] FIG. 1 is a front view showing an LED package according to a first
embodiment, FIG. 2 is a sectional view taken along an X axis of the LED
package shown in FIG. 1, and FIG. 3 is a perspective view showing the
lead frame of FIG. 1.

[0026] Referring to FIGS. 1 and 2, the LED package 100 comprises a
polygonal shape, such as a rectangular parallelepiped shape or a regular
hexahedral shape, and is classified into a side emission type LED package
and a top emission type LED package. Further, the LED package 100 can be
used as a light source for a backlight unit of an LCD or as a light unit
in an illumination field. Hereinafter, a side emission type LED package
will be described for convenience of description.

[0027] The LED package comprises a body 110 comprising a cavity 120, lead
frames 130 and 140, and a light emitting device 150.

[0028] The body 110 comprises one selected from the group consisting of
PPA (polyphthalamid), PA9T (polyamid9T), liquid crystal polymer and SPS
(syndiotactic polystyrene).

[0029] The body 110 is formed therein with the cavity 120 comprising a
predetermined depth. When a first direction is referred to as an X axis
and a second direction is referred to as a Y axis, the length of the body
110 in the X axis direction may be greater than the width of the body 110
in the Y axis direction. However, the scope of the present invention is
not limited thereto.

[0030] The lead frames 130 and 140 are formed at the upper portion of the
body 110 through injection molding. A part of the lead frames 130 and 140
is exposed to the cavity 120 of the body 110.

[0031] Referring to FIGS. 1 to 3, the lead frames 130 and 140 comprises
bottom frames 131 and 141 and sidewall frames 132 and 142 in the cavity
120, respectively. One end of the bottom frame 131 and one end of the
bottom frame 141 may serve as external electrodes 133 and 143 by passing
through the body 110 in the X axis direction, respectively. The sidewall
frames 132 and 142 are inclined outward from the Y axis, which is
perpendicular to the bottom frames 131 and 141, at a predetermined angle.
The external electrodes 133 and 143 can be provided by one of the bottom
frames 131 and 141 and the sidewall frames 132 and 142.

[0032] The lead frames 130 and 140 are formed through injection molding
using high reflective metals comprising one selected from the group
consisting of Fe, Sn, Cr, Zn, Ni, Al, Ag, Au, Cu, and an alloy thereof.

[0033] One of the lead frames 130 and 140, for instance, the lead frame
130 may have a substantially "C" shape in which three sides are bent at a
predetermined angle, and the other one of the lead frames 130 and 140,
for instance, the lead frame 140 may form the bottom frame 141. Further,
at least one of the lead frames 130 and 140, for instance, the lead frame
130 can comprise the bottom frame 131 and at least one of the sidewall
frames 132. According to the embodiment, the lead frames 130 and 140 may
have shapes different from each other. However, the scope of the present
invention is not limited thereto.

[0034] The lead frames 130 and 140 are integrally formed in the cavity 120
and may have lengths different from each other. Further, the lead frames
130 and 140 can be formed with a thickness of 20 μm to 300 μm.

[0035] A partition 125 serving as a part of the body 110 is formed between
the lead frames 130 and 140 to structurally separate the lead frame 130
from the lead frame 140. Thus, the lead frames 130 and 140 serve as
electrodes and reflect light.

[0036] Both sides (i.e. left and right sides 121 and 122) defining the
cavity 120 in the X direction are inclined at a predetermined angle and
serve as a part of the body 110. The partition 125 and the left and right
sides 121 and 122, which are disposed in the cavity 120, can be formed
together with the cavity 120 when the body 110 is formed.

[0037] The light emitting device 150 is attached to at least one of the
lead frames 130 and 140 in the cavity 120, and is connected with the lead
frames 130 and 140 through a wire 152. The light emitting device 150 can
be mounted on the lead frames 130 and 140 through wire bonding, flip
bonding, die bonding and the like.

[0038] Further, the light emitting device 150 is a III-V group compound
semiconductor and comprises one of AlGaN, GaN, InGaAlP and GaAs-based LED
chips. Further, a protective device such as a Zener diode can be mounted
on the lead frames 130 and 140 in order to protect the light emitting
device 150.

[0039] Meanwhile, the LED package 100 can be prepared in the form of a
white light emitting device using a blue LED chip and a yellow
fluorescent substance (e.g. silicate-based fluorescent substance), orange
fluorescent substance, green fluorescent substance, and red fluorescent
substance. Further, the LED package 100 can be prepared in the form of a
light source by combining at least one of a red LED chip, a green LED
chip, a blue LED chip, a yellow LED chip, a yellow green LED chip and an
UV LED chip.

[0040] In addition, a resin member (not shown) can be molded in the cavity
120 in order to protect the light emitting device 150. The resin member
can use epoxy or silicon having transparent material. If the situation
requires, fluorescent substance powder can also be added to the resin
member and molded in the cavity 120. Molding solution or additive can be
used with the resin member according to the use purpose and environment,
and the characteristics of a product. However, the embodiment is not
limited thereto. Further, the surface of the resin member has one of a
flat shape, a concave lens shape and a convex lens shape.

[0041] FIG. 4 is a sectional view taken along a Y axis of the LED package
shown in FIG. 1. Hereinafter, the lead frame 130 of the lead frames 130
and 140 will be described as an example. However, it should be noted that
the lead frames may not be formed under the same conditions as will be
described later.

[0042] Referring to FIG. 4, the body 110 has a predetermined height H1,
e.g. maximum 1 mm. For instance, the sidewall frames 132 of the lead
frame 130 has an internal angle θ1 of 30° Further, the
sidewall frames 132 can be inclined at the same angle (e.g. 15°)
or at different angles with respect to the axis perpendicular to the
bottom frame 131 of the lead frame 130.

[0043] The interval D1 between the sidewall frames 132 may vary according
to the internal angle θ1 between the sidewall frames 132 of the
lead frame 130. For instance, the bottom frame 131 of the lead frame 130
has a width W1 of 300 μm to 310 μm.

[0044] FIG. 5 is a sectional view showing the LED package comprising a
lead frame modified according to a first example embodiment. In
describing the above first example embodiment about the lead frame, the
same reference numerals are used to designate the same elements of FIG.
4, and a detailed description will be omitted in order to avoid
redundancy.

[0045] Referring FIG. 5, the height H2 of the body 110 and the width W2 of
the bottom frame 131 may be identical to or different from those of FIG.
4, respectively. For instance, an internal angle θ2 between the
sidewall frames 132 of a lead frame 130A is 45° Each sidewall
frame 132 can be inclined at an angle of 22.5° with respect to the
axis perpendicular to the bottom frame 131. As the internal angle
θ2 between the sidewall frames 132 of the lead frame 130A is
increased, an interval D2 (D2>D1) between the sidewall frames 132 can
be further widened. The interval D2 between the sidewall frames 132 is
widened, so that the surface width of the cavity 120 can be increased.

[0046] FIG. 6 is a sectional view showing the LED package comprising a
lead frame modified according to a second example embodiment. In
describing the second example embodiment about the lead frame, the same
reference numerals are used to designate the same elements of FIG. 4, and
a detailed description will be omitted in order to avoid redundancy.

[0047] Referring to FIG. 6, the height H1 of the body 110 and the width W3
of the bottom frame 131 may be identical to or different from those of
FIG. 4, respectively. For instance, an internal angle θ3 between
the sidewall frames 132 of a lead frame 130B is 60° Each sidewall
frame 132 can be inclined at an angle of 30° with respect to the
axis perpendicular to the bottom frame 131. As the internal angle
θ3 between the sidewall frames 132 of the lead frame 130B is
increased, an interval D3 (D3>D2>D1) between the sidewall frames
132 can be further widened.

[0048] FIGS. 7 to 10 are views showing lead frames modified according to
third to sixth example embodiments.

[0049] Referring to FIG. 7, the lead frame 130C comprises the bottom frame
131 and sidewall frames 132 bent from the bottom frame 131 at a right
angle. In such a case, a width W4 of the bottom frame 131 and an interval
D4 between the sidewall frames 132 are 420 μm, and a cavity depth H4
of the lead frame 130C is 300 μm to 450 μm.

[0050] Referring to FIG. 8, the lead frame 130D comprises the bottom frame
131 and one sidewall frame 132 inclined at an angle θ4 of
15° with respect to the axis perpendicular to the bottom frame
131. In such a case, a cavity depth H5 of the lead frame 130D is 338
μm to 386 μm and an interval D5 between the sidewall frames 132 is
600 μm to 626 μm. For instance, a width W5 of the bottom frame 131
is 420 μm.

[0051] Referring FIG. 9, the lead frame 130E comprises the bottom frame
131 and one sidewall frame 132 inclined at an angle θ5 of
30° with respect to the axis perpendicular to the bottom frame
131. In such a case, a cavity depth H6 of the lead frame 130E is 303
μm to 346 μm and an interval D6 between the sidewall frames 132 is
770 μm to 850 μm. A width W6 of the bottom frame 131 is about 420
μm to 450 μm.

[0052] Referring to FIG. 10, the lead frame 130F comprises the bottom
frame 131 and sidewall frames 132A inclined at a predetermined angle with
respect to the axis perpendicular to the bottom frame 131 while being
bent with a predetermined curvature. In detail, the sidewall frames 132A
are inclined at the predetermined angle and have a hemispherical shape to
efficiently reflect light.

[0053] According to the lead frames as described above, when one sidewall
frame 132 has an inclination angle of 15° to 30° with
respect to the bottom frame, the cavity depth is 250 μm to 700 μm,
and the interval between the sidewall frames 600 μm to 850 μm, the
highest efficiency is obtained. Further, the lead frame, which has high
reflective metal or is plated with high reflective metal material, has a
reflectivity of 95% or more, and has improved thermal resistance and
thermal characteristics. Further, the inclined sidewall frame can improve
the light intensity at the center area.

[0054] FIG. 11 is a graph showing an angle of the lead frame as a function
of light intensity before and after the plating in the LED package of
FIG. 4, and FIG. 12 is a graph showing an angle of the lead frame as a
function of light velocity (or light amount) before and after the plating
in the LED package of FIG. 4. The box plot shown in FIGS. 11 and 12 is
obtained using a blue LED having a specification of the same light
intensity and the same light velocity. Further, the intensity of light
and the velocity of light are measured using the same measurement
specimen.

[0055] Referring to FIGS. 11 and 12, in the LED package of FIG. 4, the
intensities of light of first to fifth LED packages #1 to #5 are measured
by changing the internal angle θ1 of the lead frame. The first,
second, third and fifth LED packages #1, #2, #3 and #5 comprise a lead
frame, which is subject to Ag-plating after the bending and punching
processes (see A). The fourth LED package #4 comprises a lead frame,
which is subject to Ag-plating before the bending and punching processes
(see B).

[0056] Further, the internal angles of the lead frames of the first to
fifth LED packages #1 to #5 are 0°, 30°, 45°,
55°, and 55°, respectively.

[0057] FIG. 11 is a graph showing the angle of the lead frame as a
function of the light intensity of the LED package, and Table 1 below
shows the result.

[0058] As shown in FIG. 11 and Table 1, the difference of 1 cd (=1000 mcd)
is generated according to the angle of the lead frame, after the plating
A, and before the plating B. The second LED package #2 has an internal
angle greater than that of the first LED package #1 by 30°, and
has a light intensity increased by 41.8%. The third LED package #3 has an
internal angle greater than that of the second LED package #2 by
15°, and has a light intensity increased by 2.6%. Further, the
fifth LED package #5 has an internal angle greater than that of the third
LED package #3 by 10°, and has a light intensity increased by
7.0%.

[0059] FIG. 12 is a graph showing the angle of the lead frame as a
function of the lumen of the LED package, and Table 2 below shows the
result.

[0060] As shown in FIG. 12 and Table 2, the difference of lumen is
generated according to the angle of the lead frame, after the plating A,
and before the plating B. The second, third and fifth LED packages have a
light velocity increased by 24%, 26.7% (=24%+2.7%) and 28.2%
(=24%+2.7%+1.5%) when the internal angle of the lead frame is increased
by 30°, 45°, and 55°, respectively.

[0061] Referring to FIGS. 11 and 12, the fourth LED package #4 has the
pre-plated lead frame and the fifth LED package #5 has the post-plated
lead frame. At this time, the fourth and fifth LED packages #4 and #5
have the same internal angles. However, since the lead frame of the
fourth LED package #4 is subject to Ag-plating before the bending and
punching processes, the Ag plating surface is damaged when bending the
lead frame. Thus, the optical efficiency deteriorates.

[0062] Accordingly, the LED package shows the optimal light intensity when
the lead frame has an internal angle of 30° to 55°.
Further, the post plating scheme exhibits optical efficiency higher than
the pre-plating scheme. Furthermore, the surface of the lead frame is
plated with high reflective metal or high reflective material, so that
the lead frame has a reflectivity of 95% or more, and improved thermal
resistance and thermal characteristics. In addition, the light intensity
at the center area can be improved by the inclined sidewall frames.

[0063] Such a LED package can be applied to an indication field, a display
field and the like, and can be provided to a terminal together with a
display device.

[0064] FIG. 13 is a perspective view showing a display device using the
LED package according to the embodiment.

[0066] The light emitting apparatus 104 comprises the LED packages 100
mounted on a substrate 102. As shown in FIGS. 1 to 3, in the LED package
100, a plurality of lead frames have a structure in which the bottom
frames are integrally formed with the sidewall frames thereof while the
sidewall frames are being bent from the bottom frames, or can be prepared
in the form of the aforementioned example embodiments.

[0067] Such a light emitting apparatus 104 corresponds to at least one
side of the light guide plate 203, and light emitted from the light
emitting apparatus 104 is incident into a lateral side of the light guide
plate 203.

[0068] The light guide plate 203 guides the incident light over the whole
area of the display device 200 and then outputs the light as surface
light. Further, a reflective pattern (not shown) can be formed at one
side of the light guide plate 203.

[0070] The light emitted from the light guide plate 203 is irradiated onto
the display panel 207 through the optical sheet 205. The optical sheet
205 comprises at least one of a diffusion sheet (not shown), a horizontal
prism sheet (not shown) and a vertical prism sheet (not shown). The
diffusion sheet is disposed on the light guide plate 203 to diffuse the
incident light. The horizontal and vertical prism sheets are disposed on
the diffusion sheet to guide the diffused light toward a display area.

[0071] The light emitting apparatus 104, the light guide plate 203 and the
optical sheet 205 can be defined as a light unit. The light unit may
comprise the reflective plate 201. Further, a part of the elements of the
light unit can be received in a structure (not shown) such as a mold
frame, a chassis structure or a metal bottom cover.

[0072] The display panel 207 serving as a liquid crystal panel comprises
two transparent substrates (not shown) and a liquid crystal, and can
display information by transmitted light and driving of the liquid
crystal. The embodiment is not limited to such a display panel 207.
Further, a display panel can be disposed at both sides of the light guide
plate 203.

[0073] Such a display device 200 can be applied to a portable terminal
such as a cell phone or a PMP, or a computer.

[0074] Although embodiments have been described with reference to a number
of illustrative embodiments thereof, it should be understood that
numerous other modifications and embodiments can be devised by those
skilled in the art that will fall within the spirit and scope of the
principles of this disclosure.

INDUSTRIAL APPLICABILITY

[0075] The embodiment can reduce optical loss in a cavity of an LED
package.

[0076] The embodiment can improve the light intensity at a center area in
a cavity of an LED package.

[0077] The embodiment can increase the amount of reflected light in a
cavity of an LED package by using a lead frame plated with reflective
metal or reflective material.

[0078] The embodiment can improve thermal resistance and thermal
characteristics of a lead frame of an LED package.